Electronic displays are commonly used to portray data in the form of visual information to be acted upon by the user. The information is typically derived from a computer and used interactively to conduct data and word processing, advertising signage, as aerospace instruments, to fly airplanes, to control machines, and the like. Today, LCDs are the leading technology for such displays. LCDs are electronic FPDs that have great industrial utility.
To more easily understand the nature of the problem addressed by the methods described herein, a brief description of the structure and operation of an LCD as an example of an FPD and of resizing an LCD follows. Additional information may be found in U.S. Pat. Nos. 7,535,547 and 7,780,492, the entire disclosures of which are expressly incorporated by reference herein.
With reference generally to FIG. 1, an LCD is made from two substrates 20 of transparent material, typically glass among other things, with a thin film of liquid crystal material sealed between the two substrates 20, thereby providing a “cell” to which external electronics (not shown) may be coupled. Spacers (not shown) may be placed in between the substrates 20 in a precise manner along with the liquid crystal material, thus forming a uniformly spaced cell, which is sealed by a perimeter seal 25. The display's active area is defined by electrodes (not shown) on the inside of the substrate in the cell area organized to address picture elements (pixels). There are many pixels electrically stimulated (controlled) to create images. Each pixel is controlled by electrodes 30 that continue outside of the seal area to the edge of the substrate(s) 20. The electrodes 30 are connected to external electronics (not shown) that, in turn, are connected to a computer or similar electrical stimulus. A pixel is formed at each intersection of a row and column line and there may be other electrical components at the intersection such as thin film transistors (TFTs), capacitors, and/or other conducting lines such as ground potential lines (also not shown). Typically, the electrodes 30 are thin film metal conductors organized in lines of rows and columns with hundreds of row and column electrodes running the full length and width of the substrate(s) 20, wherein one row electrode line and one column electrode line are associated with each pixel in a matrix-like organization. Typically, in an active matrix type LCD, all of the row and column electrodes 30 are on the inside surface of one of the substrates 20, and a common ground plane 35 is on the inside surface of the opposing substrate. The liquid crystal material and spacers are between the electrodes 30 and the ground plane 35. All of the row, column and ground plane electrodes are insulated from one another except at unique points to facilitate the operation of the display. The liquid crystal film, spacers, substrates, and the sealant enclosing the cell, are generally all dielectrics.
When a display is resized, the cell is cut, e.g., by scribing and breaking, sawing, or otherwise cutting through the substrates 20, to separate the display into a target portion 5 having a cut, exposed edge 55 and a waste portion (not shown). When this occurs, all of the thin film electrodes 30 may not separate exactly along the cut edge 55. In other words, the conductor lines 30 and the ground plane 35 may be disturbed by the resizing process, thus possibly causing undesired electrical contact in some manner.
In the simplest example, some electrodes 30 may tear loose from the substrate 20 at the cut edge 55 and make physical contact with each other or with the ground plane 35, thus causing an undesirable electrical short circuit. Examples of conductor lines 30 shorting to the ground plane 35 are shown in FIG. 1, labeled specifically as 30-s1 (representing a line that became dislodged from the substrate) and 30-s2 (representing a line that became bent). As shown in FIG. 2, sealant 45 may be applied along the cut edge 55, e.g., between the substrates 20, and this application of sealant 45 and the inevitable fluid motion may cause additional shorts. The exact detail of how the short circuits occur is not significant, as any short at the cut line will adversely affect the active image area 40 of the display. In addition, the electrodes in question may be very close such that they may short at a later time due to contamination or motion at the location in question.
Such electrical shorts may undesirably be cemented and bound together when the target portion of the display is resealed. In that case, when the display is tested and/or otherwise used to display an image, the pixels connected to the shorted row or column line(s) 30 will not respond properly to the image signal and will act as if the pixels associated with the shorted electrode have failed. Typically, this means the image would appear to have a line of failed pixels as a result of a shorted conductor line extending from the point of the short circuit along the shorted line into the image area 40. In FIG. 2, the location of an image failure resulting from a shorted conductor line 30-s1 is represented symbolically as a row of x's 50. When a short occurs, the impacted pixels and electrodes are generally in a straight line, although that may not always the case.
Multiple shorted lines may exist simultaneously. The failed pixels may only extend a short distance from the cut edge in the case of very weak shorts, or not at all if the short is so weak or not quite complete such that its effect or potential effect is not ramified in the image. Many types of shorts can occur in many ways or at different times. In such cases, the resized target display would be deemed defective unless the resized image area was restored to eliminate the resulting failed pixels caused by any shorts or belated shorts at the cut and resealed edge 55.
There is thus a desire for a method to remove any shorts caused by the process of resizing a display and/or to restore the failed pixels in the image of a resized display caused by any shorted electrical lines at the cut edge. Further, it is recommended to perform steps to ensure any shorts or belated shorts are permanently removed and do not reoccur during the operational life of the resized display.